1. Field of the Invention
The present invention relates to a cellular phone which can mount an IC card such as (for example) an SIM (subscriber identity module) card or the like, and a control method for this cellular phone.
2. Description of the Prior Art
In the GSM (global system for mobile communication) that has been standardized in Europe, an IC card called an SIM card (hereafter referred to simply as an “SIM card”) is essential. Information such as authentication algorithms, telephone numbers and the like required for calling and receiving calls is contained in this SIM card, and calling and the receiving of calls that are the intrinsic functions of a telephone can be performed by a GSM standard cellular phone by inserting this card into such a cellular phone. Specifically, in a state in which this card is not inserted, the standard is a standard that does not allow calling or the receiving of calls by the cellular phone. This concept is also continued in the IMT-2000 standard, which is called the next generation of cellular phones, and standardization as USIM (user subscriber identity module) is in progress.
MF (master files), DF (dedicated files), ADF (application dedicated files) and EF (elementary files) are contained in USIM cards as determined by the IMT-2000 standard. Information relating to authentication algorithms and telephone numbers that are required for calling and receiving calls as in the case of GSM SIM cards, and also various types of information such as telephone books and the like that are supported for the first time in USIM cards, are contained in the form of files. Information relating to the telephone numbers of the respective USIM cards is contained in a file called EF_IMSI, which is one type of the abovementioned EF, and this information is supplied to the network side.
Thus, the EF_IMSI contains information relating to telephone numbers; this information consists of country number+carrier number+serial number. This country number and carrier number indicate a certain carrier number of a certain country contracting the USIM card. The telephone number of the cellular phone that is used by inserting the USIM card corresponds to this EF_IMSI. Specifically, in cases where the country number of the EF_IMSI is (81), the telephone number of the cellular phone that is used by inserting the USIM card is the country number (81)+own-station telephone number.
In a case where a cellular phone A (containing the telephone number <81+090-0123-4567> in a USIM-A card) and a cellular phone B (containing the telephone number <81+090-8901-2345> in a USIM-B card) in which USIM cards contracted in Japan are inserted are taken to the Republic of Korea and are used to communicate with each other in the Republic of Korea, even if it is known that both cellular phones are present in the Republic of Korea, it is necessary to call by dialing the country number+own-station telephone number of the cellular phone B (81+090-8901-2345) when the cellular phone B is called from the cellular phone A.
In this case, the home location register of Japan, which is the contracting country of the USIM-B card, is first accessed. Next, processing that makes a connection with the terminal B from this home location register by international roaming is performed, so that international telephone charges must always be paid. Thus, the communications charges are not determined only by the positional relationship of the calling party and called party; besides this positional relationship, the charges also depend on the country numbers of the USIM cards possessed by the calling party and called party. In some cases, therefore, it is more convenient to insert and use a plurality of USIM cards with different country numbers.
Cellular phones equipped with a plurality of mounting parts that allow the mounting of SIM cards have conventionally been known (for example, see Japanese Utility Model Registration No. 3071509, Japanese Unexamined Patent Publication No. 2002-95038 and Japanese Unexamined Patent Publication No. 2003-244290). In the cellular phones described in three documents mentioned above, calling and the receiving of calls can be performed using a plurality of own-station telephone numbers in a single unit; accordingly, these cellular phones are superior in terms of convenience.
Furthermore, there are also cellular phones which are equipped with position information acquisition means, and in which an SIM card storing a telephone number used for calling is automatically selected from a plurality of SIM cards in accordance with position information that is acquired by these position information acquisition means (for example, see Japanese Unexamined Patent Publication No. 2002-218536). In the cellular phone described in Japanese Unexamined Patent Publication No. 2002-218536, since the SIM card storing the telephone number used for calling is automatically selected in accordance with position information so that the communications charges are lowered, the work of selecting the SIM card can be omitted, this cellular phone is superior in terms of convenience.
Meanwhile, in Japan, the spread of cellular phones has been conspicuous in recent years, and it is not unusual to find cases in which persons engaged in the bars or night clubs, or persons such as businessmen, managers, directors or the like who are provided with cellular phones by their employers, have a plurality of cellular phones used for private and public business. Furthermore, other causes of an increase in the number of cellular phones owned by a single individual include the possession of cellular phones contracted overseas in addition to cellular phones contracted in Japan by persons who work as directors in more than one country, persons who frequently make overseas business trips and the like. Because of the requirements of globalization, domestic cellular phone carriers are marketing cellular phones that can be used in more than one country (in cooperation with cellular phone firms in various countries); however, since these cellular phones have only one usable own-station telephone number, there is no change in the current situation requiring the possession of a plurality of cellular phones by persons using these cellular phones for private or public purposes, or using such cellular phone with the own-station telephone number varied according to the correspondent involved.
However, depending on the situation of the user or the like, there may be cases in which the user does not wish the correspondent to know that a plurality of SIM cards are being used. For example, if calling using the USIM-B card is automatically performed in the case of a correspondent with whom the user ordinarily communicates using the USIM-A card, this correspondent will learn the telephone number of the USIM-B card. As a result, there is some concern that it may be difficult to ensure a reliable division of use according to telephone numbers. Furthermore, there is also a danger that this will lead to a deterioration in personal relationships.
If telephone calls are made using a certain SIM card for the reason that charges are reduced due to the fact that the contracting country of this SIM card coincides with the country in which the cellular phone is used, the following problem in terms of cellular phone charges arises: namely, communications charges for private use and public use may become mixed together. Furthermore, the following problem may also be encountered: namely, even in cases where a certain cellular phone is a cellular phone used for private purposes, there may be users who wish to separate the use of an own-station telephone number used for recreational purposes and an own-station telephone number used for family purposes. As a result of such problems, users who wish to separate the use of a plurality of own-station telephone numbers encounter the following problem: namely, it is not sufficient that the communications charges be inexpensive; it is also necessary to take into account the abovementioned problems encountered in communications expenses, and the problem of the own-station telephone number becoming known to the correspondent.